The barrels. The two rotating frames with the panels showing the hours and minutes were created and installed in 1858 by Luigi De Lucia; designed to make it easier for those down in St. Mark’s Square to get a more precise idea of the time, they are among the first examples of this kind of mechanism in a public clock. The two barrels each bear twelve panels of 80 by 50 cms; one with the hours in Roman numerals, the other with intervals of five minutes in Arabic numerals. Once lighted from inside the barrels, the panels are made of sheets of blue-tinted zinc. The installation of this mechanism blocked the movement of the Three Kings, so twice a year a special mechanism to raise and lift it backwards comes into play, freeing access to the doors and the notched circle along which the Three Kings and the Angel move in procession before the statue of the Madonna.